There have been reported processes for producing 1-chloro-3,3,3-trifluoropropene by dehydrochlorinating 1,1,1-trifluoro-3,3-dichloropropane, that is obtained by chlorination of 1,1,1-trifluoropropane, with an alcoholic alkali (see Non-Patent Document 1), by adding hydrogen chloride to 3,3,3-trifluoropropine (see Non-Patent Document 2), by dehydroiodinating 3-chloro-1,1,1-trifluoro-3-iodopropane with ethanolic potassium hydroxide (KOH) (see Non-Patent Document 3), by fluorinating 1,3,3,3-tetrachloropropene or 1,1,3,3-tetrachloropropene in a pressurized liquid phase without the use of a catalyst (see Patent Document 1), and by fluorinating 1,1,1,3,3-pentachloropropane with hydrogen fluoride in a liquid phase in the presence or absence of a fluorination catalyst (see Patent Documents 2 and 3).